Maximal efficiency of heat engines may be attained if
adiabatic process is achieved, which means the process is
slow. However, this implies the output power vanishes in the
adiabatic limit. STA may be applied to heat engines to
execute adiabatic processes in finite times so that the output
power is made finite. A typical example of a quantum heat engine
is the Otto cycle with a harmonic oscillator with variable trap
frequency as working medium, in which isentropic compression
and expansion are accelerated by STA [1]}, [2]}.
